Chen, C., Sun, J., Zhang, Y., Mu, J., Li, W., Song, Y., 2020. Adsorption characteristics of CH and CO in organic- 4 2 inorganic slit pores. Fuel 265, 116969.

http://www.sciencedirect.com/science/article/pii/S0016236119323622 It is very meaningful to study the adsorption characteristics of CH and CO in shale pores in the context of CO 4 2 2 sequestration and enhanced gas recovery. However, as far as the authors' knowledge, the study of gas adsorption in organic - inorganic pores is blank. The graphene - montmorillonite (MMT) pore is proposed as a model for shale matrix, and the effect of heterogeneous surface on the adsorption behavior of CH and CO in 4 2 slit pores was studied by molecular dynamics (MD) method. More reasonable criteria have been adopted for the definition of free zones and adsorption zones. The adsorption characteristics and adsorption isotherms of CH 4 and CO were analyzed, and the microscopic mechanism of gas adsorption was revealed from the molecular 2 perspective. It was found that the heterogeneous surface caused the density distribution of the gas within the slit pores to be asymmetrical. The graphene surface shows a significantly stronger adsorption capacity than MMT, and this adsorption advantage decreases with increasing pressure. Compared with CH , the effect of 4 heterogeneous surface on CO adsorption behavior is more significant. As the pressure increases, the adsorption 2 layer of CO shows a tendency to gradually become saturated. This work provides a theoretical basis for 2 optimizing the exploitation of shale gas and geological storage of carbon dioxide.

Chen, F., Wang, X., Li, N., Cao, J., Bayon, G., Peckmann, J., Hu, Y., Gong, S., Cheng, H., Edwards, R.L., Ning, Y., Jin, M., Huang, H., Wu, C., Sun, Y., Chen, H., Zhou, Y., Chen, D., Feng, D., 2019. Gas hydrate dissociation during sea-level highstand inferred from U/Th dating of seep carbonate from the south China Sea. Geophysical Research Letters 46, 13928-13938.

https://doi.org/10.1029/2019GL085643 Abstract: Gas hydrates represent a huge reservoir of methane in marine sediments, prone to dissociation in response to environmental changes. There is consensus that past events of gas hydrate dissociation in the marine environment mainly occurred during p eriods of low sea level. Here, we report geochemical data for 2-m-thick layers of seep carbonate collected from a hydrate-bearing drill core from ~800-m water depth in the northern 18 South China Sea. The aragonite-rich carbonates reveal positive δ O values, confirming a genetic link with gas hydrate dissociation. Uranium-thorium dating of seep carbonates indicates that gas hydrates at the study site dissociated between 133,300 and 112,700 years BP, hence coinciding with the Last Interglacial (MIS 5e) sea- lev el highstand. We put forward the concept that a climate-driven increase in temperature was responsible for a period of pronounced gas hydrate dissociation. Plain Language Summary: The gas hydrate reservoir is a dynamically changing system extremely susceptible to variations of seafloor temperature and pressure. Therefore, gas hydrate dissociation and subsequent methane seepage frequently occur during times of global climate change, especially during sea-level lowstands with reduced seabed pressure. However, this conclusion was mainly based on dating of seep carbonates sampled from the seabed. As a consequence, one cannot exclude that previous results have been compromised by a sampling bias since seafloor samples are easier to collect. Authigenic seep carbonates from drill cores represent a continuous re cord of gas hydrate dynamics. Our uranium-thorium dating of seep carbonate from drill cores provides a unique example of the effects of temperature and pressure on the stability of the hydrate system in the Dongsha area, northern South China Sea (SCS), during the last interglacial stage (MIS 5e, about 130,000 years BP). Representing the most similar and most contemporary analog to the current interglacial, the study of a methane release event in the SCS during MIS 5e will shed light on the expected trend of methane release events in the future, while providing insight into the response of low-latitude oceans to climate change.

Chen, G., Chen, D., Li, F., Liu, T., Zhao, Z., Cao, F., 2020. Dual nitrogen-oxygen isotopic analysis and kinetic Pseudogulbenkiania model for enzymatic nitrate reduction coupled with Fe(II) oxidation by sp. strain 2002. Chemical Geology 534, 119456.

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